HIV infection and AIDS have no cure, in spite of recent advances in anti-HIV drugs. Many worldwide populations cannot afford the antiviral treatments for infected people. HIV vaccines offer hope for disease prevention. In this trial, 2 experimental HIV vaccines called ALVAC vCP1452 and MN rgp120 will be given to volunteers in Haiti, Brazil, Peru, and Trinidad and Tobago. The study will determine how volunteers' immune systems respond to the vaccines. (This protocol has been changed by adding new international sites.)